1. Technical Field
The present invention generally relates to a drive bit for driving a screw or bolt. More specifically, this invention relates to a drive bit suitable for gripping a screw or bolt through non-magnetic means. Class 81, Subclass 436, Screw Driver Implement, U.S. Patent Office Classification, appears to be the applicable general area of art to which the subject matter similar to this invention has been classified in the past.
2. Background Information
Drive bits are extensively used with socket drives for driving threaded screws and bolts. The simple interchangeability of the drive bits lends their use to a large variety of screw and bolt forms and sizes. However, a shortcoming with drive bits, as with all forms of screw drivers, is their inability to firmly retain the screw on the end of the bit. This is a desirable feature when the location that the screw is to be installed precludes the use of the user's hands or other means for holding the screw until the screw threads have sufficiently engaged the receiving body. One solution has been to use a magnetized drive bit to provide retention between the drive bit and screw. However, the use of a magnetized drive bit is also at times precluded when working around magnetic-sensitive equipment or hen driving non-magnetic screws such as those formed from aluminum.
There have been devices proposed for non-magnetically retaining conventional slotted screws through the use of drivers that grip the slotted screw head recess. An example of this type of retention means is U.S. Pat. No. 3,224,479 to Osborn et al. However, the Osborn device lends itself to the retention of slotted screws only and does not address many other types of screw head recess forms in use today. Examples of significance to the present invention are the Robertson, the TORX, and the hexagonal types of screw head recess forms. The three forms presented here are all characterized by relatively large screw head recesses as viewed from the screw's longitudinal axis. The Robertson form is substantially that of a square. The TORX form is substantially hexagonal with arcuate smoothly contoured concave sides and convex points. The hexagonal form takes its name literally from its geometric shape. Because of the dissimilar and unique screw head recess forms of each, the non-magnetic retention means offered by the current state of the art is impractical. Therefore, what is needed is a drive bit having non-magnetic retention means for screw head recess forms such as the Robertson, TORX, and hexagonal that can effectively and firmly grip the screw until sufficiently engaged in the receiving body.